Improvement in valves for steam-engines



UNITED STATES PATENT @FFICE.

OSCAR T. EARLE, OF SPRINGFIELD, MASSACHUSETTS.

IMPROVEMENT IN VALVES FOR STEAM-ENGINES.

Specification forming part of Letters Patent N0. 3 5,820, dated January10, 1865.

T0 aZZ whom it may concern:

Be it known that I, OSCAR T. EARLE, of Springfield, in the county ofHampden and Commonwealth of Massachusetts, have invented a new andImproved Method of Operating the Valve of a Steam-Engine; and I dohereby declare that the following is a full, clear, and exactdescription thereof, reference being had to the accompanying drawings.

It has been the endeavor of many inventors to produce a steam-valve fordirect-actin g engines, such that it could be operated by steam withoutthe use of an eccentric or other similar device requiring a crank andfly wheel.

This has been accomplished by certain combinations of steam-ports with aslide-valve. forming a part ot'or connected to a piston, which receivesa partial rotary motion sufficient to change the relative positions ofcertain ports, and thus give motion to the valve by means of steamoperating on this said piston. One such arrangement was invented byGeorge S. Faulkner, for which he obtained Letters Patent, bearing dateJanuary 27, 1863, and which Letters Patent were assigned to me; but theabove-described arrangement has this disadvantage Some mechanism isnecessary to obtain the partial rotary motion'from the reciprocatingmotion of the piston-rod, and this mechanism is necessarily of such anature as to wear rapidly, and any wear, however slight, materiallyeffects the successful opera tion of the valve.

Now, I have invented an arrangement of ports, in conjunction with aplain cylindrical slidevalve having one or more grooves or recesses onits surface, that requires no other motion except the simplereciprocating motion obtainable directly from the piston-rod. Thisfeature, in connection with the perfect balance-valve which I obtain,constitutes the principal advantages which I claim for my invention overothers in use.

To enable any person skilled in the use of steam to construct andoperate my invention, I will proceed to describe it, reference being hadto the accompanying drawings, in which- Figure 1 is a side view inpartial section of a steam-pump provided with my improved valve. Fig. 2is a cross-section of valve and chest. Fig. 3 is a horizontallongitudinal section of the steamchest with valve removed, showing theplan of valve-seat with ports.

Like letters indicate corresponding parts in each of the severalfigures. i

A is the steam-cylinder proper; B, the pistonhead. U is the steam-chest;I), the induction steam-pipe. E is the valve, which is fitted to thecylindrical chest 0. F is a steamport connecting the interior ofcylinder A with valvechest G. F, shown by dotted lines, is anothersimilar port at the other end of cylinder. G and G are the ordinaryreceiving-ports for cylinder A and chest 0. H H H are the exhaust-portsfor cylinderA and chest 0. The relative positions of the several portsare shown more clearly in Figs. 2 and 3.

I is a small port in the valve E communicating between the end of thevalve and port F when the valve is in a certain position.

I is a similar port in the other end of valve and communicating withport F.

K is a small exhaust-port communicating with end of chest E andeXhaust-port H. The

valve E is formed with three grooves of sufficient depth as to give roomfor both the supply and exhaust steam and passing'nearly around thevalve, leaving the bridges L and L, also the heads or rings a b 0 d,that fit to the cylindrical chest 0. Now, as these grooves or spacesbetween these heads or rings perform important offices, I will designatethem as 1 2 3.

. Now, the operation is as follows: In Fig. 1 the valve is shown ashavin g just been thrown to the left, and the piston B is ready to moveto the right. As the piston B now stands it covers the port F, which isclosed at the top by small bridge L on valve E between heads a and b,-but as the piston B moves to the right the lower end of port F isuncovered and live steam fills the port. Now, as the piston B moves tothe right, and just as the port F is covered by it, the arm M comes incontact with the collar 0 on the red I and moves valve E until the port1 covers over the port F then the steam passing through F and I operateson end of head a of valve E and throws it to the right, the steam at theother end of valve E exhausting through the port K till said port iscovered by head. (I of valve E, leaving the remaining steam confined bythe closing. of port K before the piston has completed its stroke toserve as a cushion to prevent the valveE from coming in violent contactwith the head R of chest 0. The port K is made very small in proportionto port F. Now, it will be seen that the piston B acts a very importantpart in the movement of the valve E, as, if in the movement of thepiston B to the right, just described, it had not covered the port F bythe time steam was let on to the end a of the valve E, the "alve wouldhave moved to a position a little past the center, at which time steamwould pass through ports G and F to the other end of valve E, and thereit would remain vibrating nearly in that position; but as the port F iscovered by piston B at the instant that port I passes over the upper endof port of F, no obstruction is ofiered to the movement of the valve.The valve E is perfectly free to move, for, as the steam is onlyreceived through the pipe D, it is confined in the groove or space 2between the heads I) and c of valve E, and, as it surrounds the valve,the pressure is balanced and a perfect balanced valve is therebyobtained, (which is also obtainable by admitting the steam through portsinto the ends of valvechest 0 and operating valve E by means ofeccentric or cranks,) and thus a certainty of operation secured which isnot attainable with any slide valve that receives the pressure of thesteam onits back. As regards the b lancing of the valve and itsoperation, in this place it would be as well if the grooves 1 and 3 werefilled solid, making one longer head, having a recess on its lower sidefor an exhaust port, on the supposition that the valve E exactly fitsthe chest; but if the valve should become slightly imperfect, by reasonof wear or other cause, any steam that may escape through fromcompartment or groove 2 by the heads b and c to the ends of the valvemight interfere with the successful and perfect operation of the valve.To avoid this the grooves 1 and 3 are made in the valve, so that anysteam leaking from 2 past heads 0 or bis received into 1 or 3, each ofwhich is in constant communication with exhaust-ports H H, and thus itis impossible for any steam to pass from 2 to either end of valve E. Thevalve E may also be provided with peculiarlyconstructed springpacking-rings, to produce a perfect fit in very large cylinders.

As regards economy of construction, this valve excels all othersheretofore constructed, inasmuch as it is one simple piece of roundcast-iron fitting into a straight cylindrical valve-chest, andconsequently involves little besides lathe-work in its construction.

Steam-pumps provided with this valve are at present, and have been forseveral months, in successful operation in many factories and publicinstitutions.

I am aware that steam has been admitted behind the forward and rear endsof a circular slide-valve from ports of the seat, but I am not awarethat a port has been made through the valve itself in the manner I haveshown and described therefore What I claim as my invention, and desireto secure by Letters Patent, is

1. A cylindrical slide-valve constructed with, one or more ports throughit, the said port or ports leading behind the ends of the valve into thesteam-chest, and at proper intervals coinciding with ports of theValveseat, substantially as and for the purposes set forth.

2. The arrangement of ports F and F with piston B and valve E, whenoperating substantially in the manner and for the purpose hereindescribed.

3. The arrangement of the ports K and K with the ports I and I and valveE, when operating substantially as herein described.

OSCAR T. EARLE.

Witnesses:

HARLEY HASKELL, W. T. GORNING.

